Hello, we had a conservatory completed in Nov 2013, by Jan 2014 we were finding water ingress into the new plaster on what had previously been the outside walls, no trays or vertical dpc were fitted by the contractor but lead flashing was fitted at the join to the house. Facing the prevailing SW wind the bricks above and to the sides of the conservatory were getting saturated in the rain and with nothing to stop it continued inwards & downwards. Trays & vertical DPC were not specified in their quote or ever mentioned. As layman we knew nothing of such things and naturally expected the finished product supplied by a seemingly reputable company to be waterproof. Should one expect the installing company to rectify this at their own cost ?